Fluid heater



Feb. 20, 1945. P. K. TURNER 2,369,993

FLUID HEATER Filed Dec. 17. 1943 Inventor: Prescott K.TU.TT1T;

by WW6? ,(fuu am His Attorngy.

Patented F eb. 20, 1945 FLUID HEATER Prescott K. Turner, Fairfield, Oonn., assignor to General Electric Company, a corporation of New York Application December 17, 1943, Serial No. 514,653

Claims. (Cl. 257-232 The invention relates to fluid heaters, particularly dual fluid heaters wherein heat is stored in one fluid and transferred to another fluid in response to flow thereof.

also the heat insulated construction now generally used, the house heatingrequirements have been materially reduced.

Thus a specific object of the present invention is to provide an automatically heated year round domestic hot water storage heater tank of ample capacity with improved forced air circulation heat transfer means for supplying the winter house heating requirements of the home.

Another object is to enable the winter air heating means to trap air around the hot water heater storage tank in the summer so as to minimize the heat loss.

A still further object is to control the air heat transfer and heat trapping action of the improved water and air heating unit by starting and stopping an air circulating fan or blower preferably under the control of a room thermostat.

A special object is to provide an improved form of fluid fiow responsive heat transfer apparatus having a series of spaced apart fins with multiple fluid inlets and outlets to the flow spaces perspective View of a combined hot water and warm air heating unit embodying the improvements of the present invention with the enclosing air flow casing and slotted air flow bafile partly cut away to reveal more clearly the detailed construction of the improved fluid flow responsive finned heat transfer apparatus, and Fig. 2 is a modification.

As shown in Fig. 1, the hot water storage tank 10 is of cylindrical form and is provided with a plurality of legs ll extending from the bottom thereof for supporting the tank above the floor level. means of a suitable automatic heater [2 which may use gas or oil or other fuel. As shown, the heater [2 is mounted centrally under the tank I!) and is provided with suitable heat exchange tubes or pipes (not shown) extending upwardly through tank ID for passing the products of combustion into heat exchange relation with the water inthe tank Ill. The products of combustion from the heater [2 are exhausted into the flue pipe 13 which extends upwardly from the top of the tank Ill.

The hot water storage tank I!) is provided with a suitable cold water inlet pipe l4 and a hot water outlet pipe I 5 which may be connected to supply the domestic hot water requirements of the home.

The automatic burner I2 is shown as of the oil burning type with the oil supplied thereto through pipe l8 and combustion air supplied thereto through pipe I 9 from suitable electrically controlled oil and air supply means 20. The oil and air supply means 20 may be of any wellknown type adapted for operation under the control of. a thermostat 2| having a temperature sentherebetween provided by a transversely slotted air, still it canbe used with equal advantage in other fluid heat transfer service if desired.

Further objects and advantages of the invention will appear in the following description of the accompanying drawing in which Fig. 1 is a sitive element 22 suitably enclosed and extending into the side of the hot water storage tank I0 so as -to be responsive to variationsin the temperature of the water therein. As shown, the thermostat 2| is of the electric circuit controlling type so as to control the energization and deenergization of the electrically operated oil and air supply means 20 to automatically maintain the temperature of the water in the tank H) at a desired value sufficient to supply all normal hot water requirements of the home both winter and summer.

In accordance with the present invention, the domestic hot water storage tank In is provided with improved heat transfer-apparatus for collecting enough of the heat from the water stored in the tank l0 through a wall of the tank to take care of the roomv heating requirements of the The water in the tank I0 is heated by home in the winter. As shown, a series of external annular heat transfer fins aremounted in spaced apart relation on the exterior of the cylindrical wall of the tank III so as to be in intimate heat conducting relation therewith for heating air. Then in order to produce an air fiow in intimate heat transfer relation with the fins 25 and the cylindrical wall of tank III, a cylindrical air fiow baflle 26, preferably formed of thin metal or other heat conducting material, is mounted in engagement with the exposed edges of the series of fins 25 so as to form restricted air flow passages 21 therebetween. The baflle 28 is provided with a plurality of air fiow inlet slots.

and a plurality of air fiow outlet slots 3| which extend transverse the series of fins 25 so as to communicate with the air fiow passages 21 therebetween. It will be understood that the fins 25 and baflle 26 structure need not be extended as near to the bottom of the water storage tank as indicated in the drawing. If desired, the fins 25 may begin about one-quarter of the height up from the bottom so as to allow for the drawing ofi of more hot water for domestic use. In such case-the bottom of the tank may become too cold for eflfective heat transfer.

An outer cylindrical enclosing casing 35, preferaby formed of heat insulating material or at least suitaby heat insulated to prevent the escape of heat, is provided for enclosing the entire water and the air heating unit. For convenience the enclosing casing may be provided with separately removable top and bottom portions 35a and 35b in order to provide ready access to the automatic burner [2 at the bottom of the unit and to the automatic air flow control valve 31 which is provided at the top of the unit. The cylindrical air flow casing 35 and the cylindrical air fiow baiile 26 are in spaced apart relation and thus form a annular air fiow passage therebetween. A forced supply of air into this passage is provided by a suitable blower 38 which may be connected, as shown, to the bottom section 35a of th enclosing casing and operated by an electric motor 39 under the automatic control or a room thermostat 40.

An annular zigzag air fiow barrier 42 extends between the outer enclosing casing 35 and the air fiow baflle 26 and is or a suitable form for segregating all of the air flow inlet slots 30 and all of the air fiow outlet slots 3| on opposite sides of the barrier 42. Thus the zigzag barrier 42 divides the air fiow space between the outer casing 35 and the flow baflle 28 into oppositely tapering inlet sections 42a and outlet sections 421: each having a corresponding inlet slot 30V or outlet slot 3| centrally communicating therewith. Consequently, when air is supplied under pressure into the bottom of the air flow space between th casing 35 and baflle 26, the resulting air flow is directed by each inlet section 42a formed by th zigzag barrier 42 through a corresponding one of the inlet slots 38 into the air flow passages 21 between the heat transfer fins 25. The air fiow into each of these passages 21 then divides .so as to pass laterally in intimate heat transfer relation over the fins and the tank I8 toward the two adjacent outlet slots 38. Thereupon the air flows into a' tapering outlet air fiow sec tion 421) formedby the zigzag barrier 42. In this way thegtotal forced air flow is subdivided into a plurality of small streams,' each having substantially the same air fiow resistance and each effective to sweep heat from the fins 25 and surface of the tank l8 due to the relatively high velocity of flow through the restricted air passages 21 between the fins.

The top of the domestic hot water storage tank III is shown provided with a suitable heat insu- .lating cover 43 formed to cooperate with the automatic air fiow control valve 31 so as to entireLv close the outlet end of the annular air fiow space between the outer casing 35 and the tank. This valve 31 enables the fiow of air over the fins 25 and tank In to be entirely stopped when the blower 38 is stopped and thereby trap the air in all the passages around the tank so as to prevent the escape of heat therefrom.

The flow control valve 31 preferably is of heat insulating material and of annular form adapted to engage with the exposed upper edge of the central section of the enclosing casing 35 and the groove 43a formed in the heat insulating cover 43 that extends over the top of the water tank 10. Th weight of annular valve 31 is suitably balanced by the tension springs 45 which are provided with adjusting screws 36 so that the flow valve 31 will be raised by the air pressure produced upon operation of the blower 38. Thus whenever the blower 38 is started into operation in response to a call for heat from the room thermostat 40, the valve 31 will be raised so as to permit the air, after passing in intimate heat transfer relation with the fins as previously described, to flow into the upper part 35b of the enclosing casing and thence be distributed through suitable distributing pipes 41 to the various rooms in the home. The fiow balancing dampers 46 may be provided in order to obtain the der sired distribution of the heated air to the rooms.

When the operation of the blower 38 is stopped due to the opening of the room thermostat 48, the flow control valve 31 will return to th closed position in which it is shown so as to prevent any 'thermosiphon circulation of the heated air to the rooms. Thus in the summer the fiow control valve 31 will remain closed to trap the air around the domestic hot water tank 10 so as to minimize the escape of heat therefrom.

If desired, a tilting damper type of air fiow responsive valve 31' biased to the closed position and substantially balanced by an adjustable weight 48 may be provided in a horizontal partition 48 of insulating material extending above the top of tank ID as indicated in Fig. 2. In this case the valve 31 will open when the blower is started and close when the blower is stopped similar to the annular spring balanced valve 21.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. Fluid fiow responsive heat transfer apparatus including a fluid flow conduit having a heat conducting wall provided with a series of heat transfer fins 'extending transversely into .said conduit, a zigzag flow barrier extending from the opposite wall into said conduit athwart said fins, and a flow directing baflle interposed between said fins and said barrier and provided with a series of flow restricting slots alternately extending transverse said fins on opposite sides ofesaid barrier.

fz-zFluid flow responsive heat transfer apparame including an annular fluid flow conduit having a heat conducting wall provided with a serie of annular heat transfer fins extending transversely into said conduit, an annular zigzag fiow barrier extending from the opposite wall into said conduit, an annular flow baflie interposed between said fins and said barrier and provided with a series of flow restricting slots alternately extending transverse said fins on opposite sides of said barrier.

3. Fluid flow responsive heat transfer apparatus including a fluid flow conduit having a heat conducting wall and a heat insulated wall and provided with a series of spaced apart heat transfer fins extending transversely in alignment from said heat conducting wall into said conduit, a zigzag flow barrier extending from said insulated wall into said conduit athwart said fins, and a flow baiiie interposed between said fins and said barrier and provided with a series of flow restricting slots alternately extending transverse said fins in parallel alignment on opposite sides of said barrier.

4. Fluid flow responsive heat transfer apparatus including a fluid flow conduit having a heated wall opposite a heat insulated wall and provided with a series of heat transfer fins extending transversely into said conduit, a zigzag flow barrier extending from said opposite wall into said said conduit athwart said fins, and a flow restricting bafile interposed between said fins-and said barrier and provided with a series of flow restricting slots alternately extending transverse said fins on opposite sides of said barrier, and flow responsive valve means closing said conduit to prevent the escape of heated fluid when the flow therethrough decreases below a predetermined value.

5. Fluid flow responsive heat transfer apparatus including a fluid flow conduit having a heat conducting wall opposite a heat insulated wall and provided with a series of symmetrically.

spaced apart heat transfer fins extending transversely into said conduit, 9. zigzag flow barrier extending from said opposite wall into said conduit symmetrically athwart said fins, a flow .baflle interposed between said fins and said barrier and provided with a series of symmetrical flow restricting slots alternately extending transverse said fins on opposite sides of said barrier, pumping means connected with one end of said conduit for forcing fluid flow therethrough to effect a transfer of heat, and automatic valve means closing the other end of said conduit when said pumping means is stopped to prevent the transfer of heat.

6. In combination, a heat conducting body having a series of spaced apart heat transfer fins extending therefrom in heat transfer relation with a fluid, a fluid flow baflle engaging the free ends of said fins to form fluid flow passages therebetween and provided with spaced apart alternate fluid inlet and" outlet slots extending transverse said flns to communicate with said passages, a casing enclosing said baflle to form a.

fluid flow space therebetween and provided with fluid inlet means at one end thereof and fluid outlet means at the other end thereof, and a zigzag fluid flow barrier extending between said baiiie and said casing for segregating said inlet slots and said inlet means from said outlet slots and said outlet means.

'7. In combination. a heat conducting cylindrical body having a series of external annular spaced apart heat transfer fins extending therefrom in heat transfer relation with a fluid, a cylindrical fluid flow baffle engaging the free ends of said fins to form fluid flow passages therebetween and provided with alternate fluid inlet and outlet slots extending transverse said fins to communicate with said passages, a cylindrical casing enclosing said baffle and provided with fluid inlet means at one end thereof and fluid outlet means at the other end thereof, and an annular zigzag fluid flow barrier extending between said bafiie and said casing for segregating said inlet slots and said inlet means from said outlet slots and said outlet means.

8. In combination, a hot water storage tank having a series of heat transfer fins extending therefrom for heating air, an air flow baffle engaging the free ends of said fins to form air flow passages therebetween and provided with spaced apart alternate air inlet and outlet slots extending transverse said fins to communicate .With said air passages, a casing enclosing said baflle to form an air flow space therebetween and provided with air inlet means at one end thereof and air outlet means at the other end thereof, and a zigzag air flow barrier extending between said baflle and said casing for segregating said air inlet slots and said air inlet means from said air outlet slots and said air outlet means.

9. In combination, a cylindrical hot water storage tank provided witha series of external annular spaced apart heat transfer fins for heating air, a cylindrical air fiow bafile enclosing said fins and provided with a series of spaced apart alternate air inlet and outlet slots extending transverse said fins to communicate with the air spaces therebetween, a cylindrical casing of heat insulating material enclosing said bailie to form an air flow space therebetween and provided with air inlet means at one end thereof and air outlet means at the other end thereof, and an annular zigzag ainflow barrier extending between said baffle and said casing for segregating said inlet slots and said inlet means from said outlet slots and said outlet means.

10. In combination, a heat conducting cylindrical water tank having means for heating the water therein and provided with a series of external annular spaced apart air heating fins, a cylindrical air flow baiile engaging said fins to form air flow passages therebetween and provided with a series of spaced apart alternate air inlet and outlet slots extending transverse said fins to communicate with said passages, a cylindrical casing of heat insulating material enclosing said baffle to form an air flow space therebetween and provided with forced air supply means at one end thereof and automatic air flow operated outlet valve means at the other end thereof, and an annular zigzag air flow barrier extending between said baflle and said casing for segregating said inlet slots and said forced air supply means from said outlet slots and said outlet valve means.

' PRESCO'I'I K. TURNER. 

